Performance and emission characteristics of a diesel engine with on-board produced hydrogen-oxygen injection

Abstract

In this research, experimental study is conducted on a generator connected to a diesel engine to enhance the performance and reduce the emissions using on-board produced H2/O2 gas mixture. The H2/O2 gas mixture is generated and supplied by a HYDI unit, which uses electrolysis of water to produce the required H2/O2 mixture. It is found that through the addition of the H2/O2 mixture via the inlet air there is significant reductions in the exhaust emissions of PM concentrations. The average reductions in PM concentrations are 10.34%, 24.77% and 41.05% across the load range at H2/O2 mixture flow rates of 0.42 LPM, 0.84 LPM and 1.25 LPM, which are equivalent to 0.022%, 0.045% and 0.067% hydrogen energy substitution (HES), respectively. The maximum reduction in exhaust emission of PM concentrations is 56% at 115.4% of the rated load with H2/O2 mixture flow rate of 0.067% HES. It is also found that there are slight reductions in the exhaust emission of CO. The average reductions in CO emissions are 5.50%, 3.40% and 2.32% across the load range at H2/O2 mixture flow rates of 0.022% HES, 0.045% HES and 0.067% HES, respectively. Since the maximum flow rate of H2/O2 gas mixture is only 0.067% HES, there is little or no change of fuel mass flowrate, thermal efficiency and bsfc. The power needed to produce H2/O2 gas mixture is provided by the battery/alternator. It only uses a little amount power of 360 W and there is no issue to start the generator after overnight shutdown. The storage and consumption of water do not possess any issue as it only consumes 0.974 L of water for 24-hours operation.